Another first has been logged on NASA's mission to Mars: converting carbon dioxide from a mean atmosphere into breathable oxygen.
The extraction of oxygen literally out of the thin and dusty air on Mars was achieved by a device on Perseverance, the rover that landed on the Red Planet on February 18 after a seven-month journey from Earth.
In its first activation, the toaster-sized instrument produced 5 grams of oxygen, or 10 minutes of breathing for an astronaut.
It works by electrolysis - using extreme heat to separate oxygen atoms from molecules of carbon dioxide, which accounts for 95 percent of Mars' atmosphere. The remaining 5 percent of the atmosphere - 1 percent as dense as Earth's - is primarily molecular nitrogen and argon.
Lots of oxygen for breathing is critical to human exploration of Mars. And getting four astronauts off its surface to go home would take seven tonnes of rocket fuel and 25 of oxygen.
Transporting a conversion machine to Mars is considered more practical than hauling oxygen in tanks.
The conversion followed a takeoff and landing of a miniature robot helicopter on Mars.